Transport Flashcards
Give 2 reasons why unicellular organisms can rely on diffusion alone
- They have a large surface area to volume ration due to their size
- They have low metabolic demands
What does the phloem transport?
Sugars like sucrose
What direction does the phloem transport sugars?
The phloem transports sugars down the plant from source to sink
What does the xylem transport?
What xylem transports water and minerals
What direction does the xylem transport water and minerals?
Up the plant (from the roots to the leaves)
How are the root hair cells adapted to their function
- Long root hair extension to increase surface area for uptake
- Thin membranes to decrease the diffusion distance
State 3 benefits of transpiration?
- The stream of water cools the plant
- The water helps to support the plant by creating turgor pressure
- The plant has a constant water supply for photosynthesis
How is the xylem adapted to transport water?
- It is waterproofed using a substance called lignin
- The xylem cells are dead and have no organelles so there is more space for water
Describe the process of transpiration
- Water is lost through the stomata
- More water is drawn up to replace the lost water
What is the transpiration stream?
The transpiration stream is the flow of water through the plant
How does temperature affect the rate of transpiration?
- As the temperature increases, so does the transpiration rate
- The molecules have more KE and evaporation happens faster
How does light intensity affect the rate of transpiration?
- The brighter the light, the more stomata are open and the rate of photosynthesis increases which both decrease the amount of water in the plant
- The rate of transportation increases
How does the wind speed affect the rate of transpiration?
The faster the wind speed, the faster the water is moved away from the plant, creating a steeper gradient and increasing the transpiration rate
Describe translocation
Translocation is the movement of sugars up or down the phloem from source to sink (with the use of energy)
Name 4 components of the blood
- Red blood cells
- White blood cells
- Platelets
- Plasma
What is the function of platelets?
Platelets are small fragments of cells that are involved in blood clotting
State 2 benefits of blood clotting
- It prevents the entry of microorganisms
- It prevents blood loss
How are red blood cells adapted to their function?
- Contain haemoglobin to carry oxygen
- Bioconcave shape to maximise surface area and allow them to squeeze through capillaries
- No nucleus to maximise space for haemoglobin
What is the purpose of plasma?
Plasma is the liquid part of the blood and its purpose is to act as a transport medium to transport CO2, hormones, nutrients and waste products
What is the function of white blood cells?
White blood cells are involved in phagocytosis and some white blood cells produce antibodies
What is a pathogen?
A disease-causing microorganism
Give 2 ways that the body can respond to detecting a pathogen
- Lymphocytes can produce antibodies that are specific to the antigens on the pathogen
- Phagocytes can engulf the pathogen
How do vaccines work?
- Dead or inactive pathogens are injected into the body
- The body produces antibodies against the pathogen
- Memory cells are also created to provide long term immunity
Describes the double circulatory system in mammals
The heart pumps blood to the lungs, the oxygenated blood returns to the heart and is then pumped around the body
What is the difference in function between veins, arteries and capillaries?
- Arteries carry blood away from the heart
- Veins carry blood towards (into) the heart
- Capillaries flow close to tissues for exchange
Describe the structure of arteries
They have thick walls made of muscle and elastic tissue, and a small lumen to transport blood under high pressure
Describe the structure of capillaries
They have thin walls about one cell thick to allow for the easy exchange of substances at the tissues
Describe the structure of veins
Veins have less muscle and elastic tissue than arteries and they have a larger lumen as the blood is at lower pressure, they also have valves to prevent backflow
Describe the blood flow through the right side of the heart
- Deoxygenated blood flows into the right atrium from the vena cava
- This blood passes through the Tricuspid Valve into the right ventricle
- The blood is then pumped out of the heart to the lungs through the right Semilunar valve and into the pulmonary artery
Describe the blood flow through the left side of the heart
- Blood enters into the left atrium from the pulmonary vein
- The blood is then pumped through the Bicuspid Valve into the left ventricle
- The blood is then pumped out through the left Semilunar Valve and into the aorta
What is the name of the wall that separates the right and left sides of the heart?
The septum
What is the name of the artery that supplies the heart tissue with blood?
The coronary artery
What type of muscle is the heart made of?
Cardiac muscle
Why is the wall of the left ventricle thicker than the wall of the right ventricle?
The left ventricle has to pump blood a further distance around the whole body so the blood needs to be under a higher pressure
What does adrenaline do to the heart rate?
Adrenaline increases the heart rate as it triggers the fight or flight reflex
State 2 parts of the body (aside from the heart) that adrenaline affects
- Adrenaline dilates the pupils
- Adrenaline increases the breathing rate
Why does the heart rate increase during exercise?
- More muscle movement requires more energy from respiration
- The muscle tissues need to be provided with a supply of oxygen to carry out respiration and so the heart needs to pump faster to provide the oxygen
What is coronary heart disease (CHD)?
When the artery providing the heart tissues with blood becomes blocked
Give 3 common risk factors for coronary heart disease
- Smoking
- Poor diet
- Lack of exercise
